Spinous process fixation apparatus

ABSTRACT

An implantable device and method for fixation of spinous processes is presented. The device has first and second spaced plates configured for attachment to portions of adjacent spinous processes. The device can also have an implant configured for insertion between two adjacent spinous processes, but need not necessarily. The method has the steps of assembling the components of the implantable device and otherwise inserting them into position onto, between, and/or adjacent two desired spinous processes.

CONTINUITY

This application claims the benefit of and is a continuation of U.S.patent application Ser. No. 13/452,587 entitled “Spinous ProcessFixation Apparatus and Method” filed on Apr. 30, 2012, which is acontinuation-in-part of U.S. patent application Ser. No. 12/960,508entitled “Spinous Process Fixation Apparatus and Method” filed on Dec.5, 2010, both of which are incorporated herein in their entirety byreference.

FIELD OF THE INVENTION

This invention relates generally to spinal surgery, and moreparticularly to devices for stabilization of the spine in associationwith placement of an interbody construct for interbody fusion or thelike.

BACKGROUND OF THE INVENTION

Varieties of interbody fusion devices are widely used following partialor total discectomies for stabilization of the spine at the site. Somestabilization devices are anchored to the pedicles. With severalsystems, the use of the pedicles requires screws or other anchoringdevices that occupy significant space and involve muscle dissection andassociated work-time for implantation. Nerve root injuries are awell-known potential complication of placement of screws in thepedicles.

The interspinous process devices are designed to increase theinterspinous process height, thereby increasing the sagittalcross-sectional area of the foramen, where the nerve roots pass away outof the spine. It is thought that these devices may also unload the facetjoints, and perhaps the intervertebral disc. They may limit spinalextension. This backward bending position may be painful for patientswith spinal stenosis because it reduces the space available for thenerve roots in the exiting foraminal openings.

In addition to interspinous process implants, interspinous processfixation devices are also common to fix adjacent spinous processes toeach other to stabilize the spinal motion-segment as an adjunct tospinal fusion. Current systems include spinous process plates that arefixed with adjacent spinous processes sandwiched therebetween.

SUMMARY

Presented herein is an implantable device for fixation of spinousprocesses. The device comprises first and second spaced platesconfigured for attachment to portions of adjacent spinous processes. Inone aspect, each plate has a first and second surface, whereby the firstsurface of the first plate is configured to face the second surface ofthe second plate.

In another aspect, the device comprises an implant with a first face, anopposed second face, a top portion, and a bottom portion. The implant isconfigured for insertion between two adjacent spinous processes. In oneaspect, the implant is an interbody cage. When positioned, the firstface of the implant faces the first surface of the first plate and thesecond face of the implant faces the second surface of the second plate.In this aspect, the first plate is connected to a portion of the implantsubstantially adjacent the first face, and the second plate is connectedto a portion of the implant substantially adjacent the second face. Itis understood that implants of varying size and shape are disclosedherein, as well as alternate embodiments with no implant.

In addition to the implantable device described herein, presented hereinis a method of fixation of spinous processes of a subject. In oneaspect, the method comprises assembling the components of theimplantable device (i.e. the first and second plates, and the implant),exposing at least one desired spinous process, inserting the implantbetween two adjacent spinous processes, joining the first and secondplates to the implant with a portion of the spinous processes beingtherebetween, compressing the plates onto the first and second spinousprocesses, and maintaining the compression of the plates while affixingthe plates with respect to the implant.

Related methods of operation are also provided. Other apparatuses,methods, systems, features, and advantages of the interspinous processdevice and the method of its use will be or become apparent to one withskill in the art upon examination of the following figures and detaileddescription. It is intended that all such additional apparatuses,methods, systems, features, and advantages be included within thisdescription, be within the scope of the interspinous process device andthe method of its use, and be protected by the accompanying claims.

DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate certain aspects of the instantinvention and together with the description, serve to explain, withoutlimitation, the principles of the invention. Like reference charactersused therein indicate like parts throughout the several drawings.

FIG. 1 is a perspective view of one aspect of an implantable device forthe fixation of spinous processes, shown in-situ between first andsecond spinous processes;

FIG. 2 is a perspective view of one aspect of the implantable device ofFIG. 1;

FIG. 3 is a rear elevational view of the implantable device of FIG. 2;

FIG. 4 is right side view of the implantable device of FIG. 2;

FIG. 5 is a plan view of the implantable device of FIG. 2;

FIG. 6 is cross-sectional bottom elevational view of the implantabledevice of FIG. 2, cut along line 6-6 in FIG. 3;

FIG. 7 is an exploded perspective view of the implantable device of FIG.2;

FIG. 8 is a perspective view of one aspect of the implantable device forthe fixation of spinous processes;

FIG. 9 is a rear elevational view of the implantable device of FIG. 8;

FIG. 10 is right side view of the implantable device of FIG. 8;

FIG. 11 is a plan view of the implantable device of FIG. 8;

FIG. 12 is cross-sectional bottom elevational view of the implantabledevice of FIG. 8, cut along line 12-12 in FIG. 9;

FIG. 13 is an exploded perspective view of the implantable device ofFIG. 8;

FIG. 14 is a perspective view of one aspect of the implantable devicefor the fixation of spinous processes showing one aspect with at leastone substantially flexible post;

FIG. 15 is a rear elevational view of the implantable device of FIG. 14;

FIG. 16 is right side view of the implantable device of FIG. 14;

FIG. 17 is a plan view of the implantable device of FIG. 14;

FIG. 18 is cross-sectional bottom elevational view of the implantabledevice of FIG. 14, cut along line 18-18 in FIG. 15; and

FIG. 19 is an exploded perspective view of the implantable device ofFIG. 14.

FIG. 20 is a perspective view of one aspect of an implantable device forthe fixation of spinous processes, shown in-situ between first andsecond spinous processes;

FIG. 21 is a perspective view of one aspect of the implantable device ofFIG. 20;

FIG. 22 is an exploded perspective view of the implantable device ofFIG. 20;

FIGS. 23A-23C are cross-sectional bottom elevational views of theimplantable device of FIG. 20, showing the first plate and the secondplates at various angles with respect to one another;

FIGS. 24A and 24B are partially transparent top plan views of theimplantable device of FIG. 20, showing the two plates having the abilityto be connected at various connection points on the post and having theability for polyaxial movement with respect thereto;

FIG. 25 is left side elevational view of one aspect of a first plate ofthe implantable device of FIG. 20;

FIG. 26 is a right side elevational view of one aspect of a first plateof the implantable device of FIG. 20, showing an implant positionedthere between the first and second spaced plates;

FIG. 27 is a right side elevational view of one aspect of a second plateof the implantable device of FIG. 20;

FIG. 28 is a front cross-sectional elevational view of the implantabledevice of FIG. 20;

FIG. 29 an exploded perspective view of the implantable device of FIG.20, showing the post positioned therethrough an implant;

FIG. 30 is an exploded perspective view of the implantable device ofFIG. 20, showing the device without an implant;

FIG. 31 is an exploded perspective view of one aspect of an implantabledevice for the fixation of spinous processes, showing an embodimentwherein a first post is configured to be telescopingly received by aninterior longitudinal cavity of a second post.

DESCRIPTION OF THE INVENTION

The present invention can be understood more readily by reference to thefollowing detailed description, examples, and claims, and their previousand following description. Before the present system, devices, and/ormethods are disclosed and described, it is to be understood that thisinvention is not limited to the specific systems, devices, and/ormethods disclosed unless otherwise specified, as such can, of course,vary. It is also to be understood that the terminology used herein isfor the purpose of describing particular aspects only and is notintended to be limiting.

The following description of the invention is provided as an enablingteaching of the invention in its best, currently known aspect. Thoseskilled in the relevant art will recognize that many changes can be madeto the aspects described, while still obtaining the beneficial resultsof the present invention. It will also be apparent that some of thedesired benefits of the present invention can be obtained by selectingsome of the features of the present invention without utilizing otherfeatures. Accordingly, those who work in the art will recognize thatmany modifications and adaptations to the present invention are possibleand can even be desirable in certain circumstances and are a part of thepresent invention. Thus, the following description is provided asillustrative of the principles of the present invention and not inlimitation thereof.

As used herein, the singular forms “a,” “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to a “plate” includes aspects having two or moreplates unless the context clearly indicates otherwise.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another aspect includes from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint.

As used herein, the terms “optional” or “optionally” mean that thesubsequently described event or circumstance may or may not occur, andthat the description includes instances where said event or circumstanceoccurs and instances where it does not.

In one aspect, presented herein is an implantable device 10 for fixationof spinous processes. The device comprises first and second spacedplates 100, 200 configured for attachment to portions of adjacentspinous processes. In one aspect, each plate has a first and secondsurface, whereby the first surface 110 of the first plate 100 isconfigured to face the second surface 210 of the second plate 200.

In another aspect, the device comprises an implant 300 with a first face310, an opposed second face 320, a top portion 330, and a bottom portion340. The implant 300 is configured for insertion between two adjacentspinous processes. In one aspect, the implant is an interbody cage. Whenpositioned, the first face 310 of the implant faces the first surface110 of the first plate 100 and the second face 320 of the implant facesthe second surface of the second plate 200. In this aspect, the firstplate is connected to a portion of the implant substantially adjacentthe first face, and the second plate is connected to a portion of theimplant 300 substantially adjacent the second face.

It is beneficial for the plates to be able to move with respect to theimplant in order to adjust to the contour of the portions of the spinousprocesses onto which they attach. In one aspect, the plates can movepolyaxially with respect to the implant. In another aspect, one or bothof the first and second plates are pivotally connected to the respectiveportions of the implant. As such, there exist several options toaccomplish this feature.

In one aspect, the implant comprises a first post 120 projectingtherefrom the first face and a second post 220 projecting therefrom thesecond face. As illustrated in FIG. 7, in one aspect, the first andsecond posts are substantially normal to the respective first and secondfaces. However, it is contemplated that the first and second post can bepositioned at an acute angle relative to the respective first and secondfaces of the implant 300.

In another aspect, the first plate comprises a first socket 130 forcomplimentary receipt of the first post 120 and the second plate 200comprises a second socket 230 for complimentary receipt of the secondpost 220. In this aspect, a first internal collar 140 can be positionedwithin the first socket 130 and a second internal collar 240 can bepositioned within the second socket 230. The collars, thus, can beconfigured to engage a portion of the respective first and second posts.In yet another aspect, each internal collar can be configured to pivotwithin each respective socket, thereby permitting polyaxial movement ofthe first and second plates with respect to the implant. The collars canhave an external diameter that is larger than the diameter of thesocket, thereby resisting movement of the collars into or out of thesocket. Additionally, the collars may comprise a slit, which can becompressed for insertion into each socket during manufacturing.

In one exemplified aspect, there can be set screws 150, 250 configuredto interface with each collar to tighten the collars thereto therespective first and second posts. The collars are configured tointerface at a desired connection point along the particular post withwhich it interfaces, thereby selectively controlling the distancebetween the first and second surface of the first and second plates,respectively.

In another aspect, in lieu of, or in addition to, the polyaxial movementpermitted by the collar and socket combination, the posts may compriseflexible material, thereby permitting polyaxial movement of the firstand second plates with respect to the implant. As such, the plates canbe connected thereto the posts without the use of collars, as shown inFIGS. 14-19.

In another exemplified aspect, as shown in FIG. 13, the posts canproject therefrom the first and second surfaces of the first and secondplates, respectively, rather than from the first and second faces 310,320 of the implant. As such, in one aspect, the first and second postsare substantially normal to the respective first and second surfaces. Inthis aspect, the implant comprises a first socket for complimentaryreceipt of the first post and a second socket 230 for complimentaryreceipt of the second post.

Similar to the aspect described above, in another aspect, a firstinternal collar 140 is positioned within the first socket 130 and asecond internal collar 240 is positioned within the second socket. Thefirst and second collars are configured to engage a portion of therespective first and second posts 120, 220. In one aspect, they canengage the posts along the length of the post, thereby allowing forvariance in the distance between the two plates.

In one exemplified aspect, each internal collar can pivot within eachrespective socket, thereby permitting polyaxial movement of the firstand second plates with respect to the implant 300. Additionally, asmentioned herein, in another aspect, the first post and the second postare flexible, thereby permitting polyaxial movement of the first andsecond plates with respect to the implant.

At least one of the first and second surfaces 110, 210 of the plates100, 200, in one aspect, comprises teeth 160, 260 for frictionalengagement of spinous processes. As can be appreciated, both the firstand second surfaces can comprise teeth. The teeth 160, 260, for example,engage the spinous processes when the plates are clamped thereon.

In another exemplified aspect, the top portion 330 of the implantdefines a longitudinal trough 350 configured for complimentary receiptof a portion of a first spinous process 400. As can be appreciated byone skilled in the relevant art, the bottom portion 340 of the implantmay likewise define a longitudinal trough 350 configured forcomplimentary receipt of a second spinous process 410, which would beadjacent the first spinous process 400.

The longitudinal trough of the top portion can also comprise externaledges that have a plurality of consecutive ridges 360 configured forfrictional engagement with a portion of the first spinous process. Ascan be appreciated, the longitudinal trough of the bottom portion mayalso have external edges with pluralities of consecutive ridges 360 forfrictional engagement with a portion of the second spinous process 410.For ease of insertion, the implant can also comprise a tapered distalnose, as illustrated in FIG. 7.

As can be appreciated by one skilled in the art, at times, it can bebeneficial to have, in addition to the mechanical fixation, a fusion orother bonding component of the implantable device explained herein. Inone exemplified aspect, the implant 300 defines an internal cavity 370in communication with at least one of the top portion and the bottomportion. In another aspect, the internal cavity 370 is in communicationwith both the top portion and the bottom portion. In use, theprofessional may introduce bone cement or bone graft material into theinternal cavity to assist in fusion or bonding of the implant with thesurrounding spinous processes.

In addition to the implantable device described herein, presented hereinis a method of fixation of spinous processes of a subject. The methodcomprises assembling the components of the implantable device into animplant assembly (i.e. the first and second plates, and the implant),exposing at least one desired spinous process, inserting the implant 300between two adjacent spinous processes, joining the first and secondplates to the implant with a portion of the spinous processes beingpositioned therebetween, compressing the plates onto the first andsecond spinous processes, and maintaining the compression of the plateswhile affixing the plates with respect to the implant.

As mentioned herein, the implant can comprise a first and second postextended therefrom the first and second faces of the implant 300, eachpost configured for engagement with the first and second plates. In thisaspect, the step of joining the first and second plates with the implantcan comprise sliding the first plate 100 onto the first post 120 and thesecond plate 200 onto the second post whereby portions of the first andsecond spinous processes are positioned in a space between the first andsecond surfaces and affixing the first plate to the first post and thesecond plate to the second post. Where the first and second platescomprise collars with set screws, affixing the first and second platesonto the first and second posts can comprise merely tightening the setscrews.

In one aspect of the method, the method comprises the step of angulatingone or both of the first and second plates relative to each other in atleast one plane during compression on the spinous process. In anotheraspect, the method comprises angulating the two plates in two planesduring compression of the plates onto the spinous processes. In anexemplified aspect, the two planes are the coronal and axial planes.

As described, in one aspect, the implant defines an internal cavity incommunication with its top and bottom portions. In another aspect, themethod further comprises introducing bone graft material into theinternal cavity, where the material is selected from the groupconsisting of autologous bone, allograft bone, bone substitute, andosteoinductive agent. In still another aspect, the method comprisesintroducing bone cement into the internal cavity.

In yet another exemplified aspect, the implantable device can comprisetwo spaced plates connected via a single post 520. In this aspect, animplant may or may not be present. In one aspect, the implantable devicecomprises first and second spaced plates 100, 200, the first plate 100having a first surface 110 facing a second surface 210 of the secondplate 200. In this aspect, the post 520 is connectable to the first andsecond plates. The post, in this aspect, has a first end portion 522, asecond end portion 524, and a middle portion 526, where the first plate100 is configured to connect to the first end portion 522 of the post520 and the second plate 200 is configured to connect to the second endportion 524 of the post.

As with other aspects disclosed herein, in one aspect, the implantabledevice is configured for polyaxial movement of the first and secondplates with respect to at least portions of the post 520 when the firstand second plates are connected to the post. As with the other aspectsdescribed herein, the first and/or second plate can be configured topivotally connect to a portion of the respective end portion of thepost. Additionally, as described above, the first and second plates canbe configured to connect to the post at a first and second connectionpoint 530, 532, respectively. The connection points can be adjustable tocontrol the distance between the first and second surfaces. In thisaspect, the polyaxial movement of the plates with respect to the postcan be accomplished in the various manners described herein above.

In one aspect, an implant 300, such as the ones described herein, can bepositioned therebetween the first and second spaced place. In thisaspect, at least a portion of the post is configured to passtherethrough a portion of the implant. In this aspect, the implantdefines an aperture 380 through which the post can pass. The implant mayalso define an internal cavity (graft window) 370 for introduction ofbone cement or bone graft material into the internal cavity to assist infusion or bonding of the implant with the surrounding spinous processes.

In this aspect, the implantable device leads to a method of fixation ofspinous processes of a subject. In one aspect, the method comprisesassembling components into the described implant assembly, exposing adesired spinous process, connecting the first plate 100 to a portion ofthe first end portion 522 of the post, inserting the middle portion 526of the post between adjacent spinous processes to position the postsubstantially between a first spinous process and a second spinousprocess, sliding the second plate 200 onto a portion of the second endportion 524 of the post 520 whereby portions of the first and secondspinous processes are positioned in a space between the first and secondsurfaces, compressing the plates onto the first and second spinousprocesses; and maintaining compression of the plates onto the first andsecond spinous processes while affixing the first plate to the first endportion and the second plate to the second end portion.

This aspect of the method can also comprise angulating the first platerelative to the second plate in at least one plane during compression ofthe plates on the spinous processes. In an exemplified aspect, the stepof angulating the first plate relative to the second plate comprisesangulating the two plates in two planes during compression of the platesonto the spinous processes. In another aspect, the angulation of thefirst plate relative to the second plate is in coronal and axial planes.The method can also comprise means for pivotally connecting the firstand second end portions, respectively.

In still another aspect, the implantable device can comprise the firstand second spaced plates 100, 200 with a first post 120 having a firstend 122 pivotally connected to the first surface 110 of the first plate100 and a second end 124 spaced therefrom the first surface, as well asa second post 220 having a second end 222 pivotally connected to thesecond surface 210 of the second plate 200 and a first end 224 spacedtherefrom the second surface. In this aspect, the second post is atleast partially tubular, defining an interior longitudinal cavity 226.Additionally, in this aspect, at least a portion of the first post isconfigured to be telescopingly received by the interior longitudinalcavity. The position of the first post relative to the second post canbe fixed using a set screw 228 positioned through a portion of thesecond post configured to engage the first post and maintain itsposition. The position may also be fixed using a collar or band around aportion of the second post that tightens in any known fashion. Thesecond post may also be crimped onto the first post. Other knownfixation means can also be employed.

As with the various aspects described herein, an implant can bepositioned therebetween the first and second spaced plates. In thisaspect, at least a portion of at least one of the first and second postsis configured to pass therethrough a portion of the implant.

In one exemplified aspect, the first plate 100 comprises a first socket130 for complimentary receipt of the first end 122 of the first post120, and the second plate 200 comprises a second socket 230 forcomplimentary receipt of the second end 222 of the second post 220. Aswith the other aspects described herein, there can be a first internalcollar 140 within the first socket and a second internal collar 240within the second socket. As such, the first collar is configured toengage a portion of the first end of the first post and the secondcollar is configured to engage a portion of the second end of the secondpost. In one aspect, each internal collar is configured to pivot withineach respective socket, thereby permitting the polyaxial movement of thefirst and second plates with respect to the first and second posts,respectively. A first set screw can also be configured to interface withthe first collar, and a second set screw can be configured to interfacewith the second collar to tighten the collars thereto the respectivefirst and second posts.

As an alternative to the internal collars used for polyaxial movement,or in addition thereto, in one aspect, the first and second posts can besubstantially flexible, thereby permitting the polyaxial movement of thefirst and second plates with respect to the respective first and secondpost.

Although several aspects of the invention have been disclosed in theforegoing specification, it is understood by those skilled in the artthat many modifications and other aspects of the invention will come tomind to which the invention pertains, having the benefit of the teachingpresented in the foregoing description and associated drawings. It isthus understood that the invention is not limited to the specificaspects disclosed hereinabove, and that many modifications and otheraspects are intended to be included within the scope of the appendedclaims. Moreover, although specific terms are employed herein, as wellas in the claims that follow, they are used only in a generic anddescriptive sense, and not for the purposes of limiting the describedinvention.

What is claimed is:
 1. An implantable device for fixation of spinousprocesses, comprising: first and second spaced plates, the first platehaving a first surface facing a second surface of the second plate; anda post having a longitudinal length; a means to translate the firstplate along at least a portion of the longitudinal length of the post,move the first plate polyaxially with respect to the post, and directlyattach the first plate to the post at a desired position along it'slongitudinal length to fix its position and orientation relative to thepost; and a means to translate the second plate along at least a portionof the longitudinal length of the post, move the second platepolyaxially with respect to the post, and directly attach the secondplate to the post at a desired position along its longitudinal length tofix its position and orientation relative to the post.
 2. Theimplantable device of claim 1, further comprising an implant positionedtherebetween the first and second spaced plates, wherein at least aportion of the post is configured to pass therethrough a portion of theimplant.
 3. The implantable device of claim 1, wherein the first platecomprises a first socket for complimentary receipt of a first endportion of the post and wherein the second plate comprises a secondsocket for complimentary receipt of a second end portion of the post. 4.The implantable device of claim 3, further comprising a first internalcollar within the first socket and a second internal collar within thesecond socket, wherein the first collar is configured to engage aportion of the first end portion of the post and the second collar isconfigured to engage a portion of the second end portion of the post. 5.The implantable device of claim 4, wherein each internal collar isconfigured to pivot within each respective socket, thereby permittingthe polyaxial movement of the first and second plates with respect tothe post.
 6. The implantable device of claim 4, further comprising afirst set screw configured to interface with the first collar, and asecond set screw configured to interface with the second collar totighten the collars thereto the respective first and second endportions.
 7. The implantable device of claim 1, wherein the post issubstantially flexible, thereby permitting the polyaxial movement of thefirst and second plates with respect to the middle portion of the post.8. The implantable device of claim 1 wherein at least one of the firstand second surfaces comprises teeth for frictional engagement of spinousprocesses.
 9. An implantable device for fixation of spinous processes,comprising: first and second spaced plates, the first plate having afirst surface facing a second surface of the second plate; anintervertebral cage positionable between the first and second spacedplates, the intervertebral cage defining a post aperture therethrough; apost having a longitudinal length; a means to translate the first platealong at least a portion of the longitudinal length of the post, movethe first plate polyaxially with respect to the post, and directly affixthe first plate to the post at a desired position along its longitudinallength to fix its position and orientation relative to the post; and ameans to translate the second plate along at least a portion of thelongitudinal length of the post, move the second plate polyaxially withrespect to the post, and directly affix the second plate to the post ata desired position along its longitudinal length to fix its position andorientation relative to the post.
 10. The implantable device of claim 9,wherein the post is substantially flexible, thereby permitting thepolyaxial movement of the first and second plates with respect to themiddle portion of the post.